This invention relates to an arrangement for locating concrements in a patient's body, consisting of a sound source, a coupling arrangement between the sound source and the patient for introducing generated sound waves into the patient's body and an arrangement on the patient's skin for producing a marking in the resulting sound image.
Known devices for applying markings on the skin of a patient are usually coordinated specifically with the particular locating device with which they are mechanically and/or electrically connected. By means of such a marking arrangement, it is possible, after locating a concrement which is to be broken up, to optically mark the skin surface, for example, optically, by means of the locating device. In this manner a therapy head, which generates shock waves for breaking up the concrement, can be aligned at a predetermined position relative to the marking, in order to permit an optimal introduction of the treatment shock waves into the body.
The applicant's German patent document DE-PS 40 03 350 describes an arrangement for positioning an adjustable C-arc X-ray apparatus having an X-ray tube and an image intensifier, with respect to a device for treating patients with extracorporeally generated, focussed shock waves, particularly on a lithotriptor. At least two light sources fastened to the X-ray apparatus generate light beams which cross one another in the isocenter of the C-arc. A reference element, which can be mounted on the treatment unit of the shock wave apparatus, indicates the position of the therapy focus.
In addition, the applicant's German patent document DE-PS 40 33 439 describes a targeting device for X-ray locating in the extracorporeal treatment of patients by means of focussed shock waves, particularly for a lithotriptor. The targeting device consists of a support on or in which X-ray-positive elements are arranged such that they point to the focal spot of the shock wave system. The position of the elements in the x-ray image clearly indicates the position of the focal spot.
As initially mentioned, in the case of the two known devices, the respective marking arrangements are aligned specifically for use with the associated locating arrangements, and cannot be used with other lithotriptors or their locating arrangements.
It is an object of the present invention to provide an arrangement for generating a marking of the location of a therapy focus in a patient which cooperates with any sound source and which permits the injection of the marking at a freely selectible point into the sonic image, so that the location of the focus for the sound therapy apparatus can be shown in the sound image.
This and other objects and advantages are achieved by the marking arrangement according to the invention, in which a sensor array is transparent to the emitted sound waves from the sound source of a given ultrasound image generating apparatus. After the elapse of a set time period following the emission of a sound pulse from the imaging sound source (which period corresponds to the propagation time of a sound pulse to and from a location in space and a direction from the sensor array), the sensor array, which comprises an array of acoustic sensor elements, generates a sound signal that is superimposed as a marking in the form (for example) of a light spot or a graticule at an arbitrarily selectable point on the sonically generated image.
The invention therefore makes it possible to insert a suitable marking, such as a graticule or a light spot, at any point into the sonically generated image, specifically without any electric intervention in the control arrangement of the sound source of the imaging device. Thus, the sound source may be of an arbitrary design, such as for example a conventional medical multi-element scanner or a rotating element scanner.